Functional element for attaching to a sheet metal part composite component produced from said element and method for attaching the functional element to a sheet metal part

ABSTRACT

The invention relates to a functional element for attaching to a sheet metal part, such as for example a nut element or a bolt element comprising a body section or head section, which has a requisite cylindrical part on one axial end and runs into a cylindrical rivet section on its other axial end. Said element is characterised in that the body section is provided with an essentially cone-shaped region between the first axial end or a cylindrical section that may be provided there and the rivet section, said region forming a bearing surface for a corresponding cone-shaped region of a sheet metal part and that the cylindrical part, if present, has a diameter at the border with the cone-shaped region that is no greater than the maximum diameter of said cone-shaped region. When the functional element is attached to the sheet metal part, the narrow end of the cone-shaped region of said metal part is clamped in an annular protrusion, formed by the rivet section. The invention also relates to and discloses a composite component and to a method for attaching a functional element.

The present invention relates to a functional element for attachment toa sheet metal part such as for example a nut element or a bolt elementhaving a body part or head part respectively which has at its firstaxial end, if required, a circularly cylindrical part and which mergesat its other axial end into a cylindrical rivet section, in accordancewith the preamble of claim 1, and also relates to a component assemblymanufactured from the functional element and a sheet metal part inaccordance with the preamble of claim 17.

A functional element of the initially named kind is offered by thecompany Profil Verbindungstechnik GmbH & Co. KG, Friedrichsdorf,Germany, under the designation EMF in the form of a nut element. Withthis element a component can be attached to the side of the sheet metalpart remote from the ring flange and indeed by means of a threaded boltwhich engages into the thread of the nut element and clamps thecomponent and the sheet metal part against one another. The element isattached to a sheet metal part by means of the method which is describedin EP-A-0 713 982 in conjunction with its FIGS. 16 and 17, with thismethod being claimed per se in the corresponding European DivisionalApplication EP-A-0 922 866. A functional element of the initially namedkind in the form of a bolt element is likewise known and indeed in theform of a so-called SBF bolt element of the company ProfilVerbindungstechnik GmbH & Co. KT which is described, amongst otherthings, in the German Patent 34 47 006 together the associatedattachment method. Both the EMF element and also the SBF element haveproved themselves in practise. With the EMF element the sheet metal partis only insignificantly deformed and remains, in the region ofattachment of the functional element, at least substantially in the sameplane as the surrounding sheet metal material.

In contrast, with the SBF bolt, a rounded recess is produced in thesheet metal part and this leads to a relatively stiff attachment of thebolt element to the sheet metal part.

The object underlying the present invention is to provide a functionalelement which ensures a stiff attachment to the sheet metal part, sothat tensile forces and compression forces and also transverse forcesand shear forces can be transmitted via the element to the sheet metalpart, with the attachment being intended to have a long working lifeeven with alternating loading and not tending to the formation offatigue cracks. Furthermore, the invention intends to provide acomponent assembly comprising the functional element and a sheet metalpart which has corresponding characteristics and to make available amethod for the attachment of the functional element which ensures a highquality attachment of the functional element to the sheet metal partwithout being particularly complicated in its realization. In addition,the functional element should be suitable for an electric terminalelement, for example in the form of an earthing bolt.

In this application the designation “functional element” has its normalmeaning, the examples for such functional elements are fastener elementssuch as nut elements and bolt elements which enable the attachment of afurther component to a sheet metal part. The designation however alsoincludes all other types of hollow elements which for example serve toreceive inserted parts or as a rotatable support for a shaft as well asall elements which are provided with a shaft part, for example toreceive a clip or for the rotary mounting of a hollow part.

In order to satisfy the object a functional element of the initiallynamed kind is provided in accordance with the invention which ischaracterized in that the body part is provided in the region betweenthe first axial end, or any circularly cylindrically part providedthere, and the rivet section with an at least substantially conicalregion which forms a contact surface for a corresponding conical regionof a sheet metal part and in that the circularly cylindrical part, ifpresent, has a diameter at the boundary to the conical region which isnot larger than the maximum diameter of the conical region and thus doesnot form a ring flange there.

A corresponding component assembly is characterized in that the bodypart is provided in the region between the first axial end, or anycircularly cylindrically part provided there, and the rivet section withan at least substantially conical region which forms a contact surfacefor a corresponding conical region of the sheet metal part and in thatthe circularly cylindrical part, if present, has a diameter at theboundary to the conical region which is not larger than the maximumdiameter of the conical region and thus does not form a ring flangethere, wherein a conical region of the sheet metal part is trapped in aring bead formed from the rivet section and in that the conical regionof the sheet metal part contacts the conical region of the functionalelement at least substantially over its full area.

This embodiment of the functional element, or of the component assemblyformed with the functional element, thus leads to a formation in whichthe conical region of the sheet metal part contacts the conical regionof the body part of the functional element at least substantially overits full area. This construction provides a particularly stiff and firmattachment of the functional element of the sheet metal part and thussatisfies the subject of the object set out above.

This full area contact leads to a situation in which relative movementsbetween the sheet metal part and the element are largely precluded. Thisalso increases the stiffness of the connection and helps avoid theformation of fatigue cracks.

It is particularly favourable when features providing security againstrotation are provided in the region of the conical surface since thesheet metal material can be brought into engagement with these featuresproviding security against rotation, whereby the security againstrotation is achieved without reducing the stiffness of the connection.The features providing security against rotation can, for example,advantageously have the form of noses and/or recesses.

The axial length of the conical surface should correspond at leastapproximately to twice the sheet metal thickness, preferably toapproximately four times the sheet metal thickness. A dimension of thiskind ensures that the conical region is adequately long in order toachieve the desired stiffness.

The enclosed cone angle of the conical surface preferably lies in therange between 60° and 150°. An enclosed cone angle in the range between70° and 140° and in particular a cone angle of 75° to 150° isparticularly preferred. An enclosed cone angle of approximately 90°counts as particularly preferred.

It is particularly favourable when the conical surface merges via acylindrical neck part into the rivet section. This neck part isessentially not deformed during the deformation of the material of thefunctional element in the region of the rivet section and forms a partof the clamping recess for the sheet metal material in the region of theedge of the hole provided in the sheet metal material. The neck partcan, with advantage, have an axial length which correspondsapproximately to the sheet metal thickness and is preferably somewhatlarger than this.

The axial height of the circularly cylindrical part can be reduced tozero so that the end face of the conical region with the largestdiameter comes to lie at the surface of the sheet metal part remote fromthe rivet bead or lies somewhat higher or lower than this surface.

The possibility also exists however of making the axial thickness of thecircular cylindrical part significantly larger than the thickness of thesheet metal part to which the element is to be secured. In this case theend face of the circularly cylindrical part remote from the sheet metalpart projects significantly in front of the corresponding top side ofthe sheet metal part and can for example be exploited to realize aspacer function. In both cases the conical surface in the region of theside of the sheet metal part remote from the rivet bead can be executedwith a relatively large diameter so that on the whole a large supportsurface is present between the functional element and the sheet metalpart, whereby a favourable surface pressure is achieved and thetransmission of forces via the functional element into the sheet metalpart can be favoured. Particularly preferred embodiments of thefunctional element and also of the component assembly can be found inthe subordinate claims.

The attachment of the functional element to a sheet metal part can takeplace amongst other things with a method which is essentially known fromthe German Patent 34 47 006, with the shape of the die being adapted tothe special shape of the sheet metal part of the functional element.

The invention will be explained in more detail in the following withreference to embodiments and to the drawings which show:

FIG. 1 a functional element in the form of a nut element partlysectioned in the axial direction,

FIG. 2 a schematic representation of a sheet metal part which isprepared to receive the functional element of FIG. 1,

FIG. 3 a component assembly which is formed from the functional elementof FIG. 1 and the sheet metal part of FIG. 2,

FIG. 4 a side view of a functional element in the form of a bolt elementpartly sectioned in the longitudinal direction,

FIG. 5 an end view of the bolt element of FIG. 4 corresponding to thearrow direction V of FIG. 4,

FIG. 6 a perspective representation of the bolt element of FIGS. 4 and5,

FIG. 7 a drawing similar to FIG. 6 of the same subject but to adifferent scale and with a section plane which extends through a noseproviding security against rotation,

FIG. 8 a representation of the bolt element of FIGS. 4 to 7 in the viewof FIG. 7 but with a nut element screwed onto the shaft part 128, inparticular for the formation of an electrical connection bolt,

FIG. 9 an end view of the bolt and nut combination of FIG. 8 seen in thearrow direction I of FIG. 8, and

FIG. 10 a partly sectioned representation of a component assembly whichis formed from the bolt element of FIG. 8 and a sheet metal part.

FIG. 1 shows a functional element 10 having a one-piece body part 12which has no ring flange but rather a conical surface 16 which mergeswithout a ring flange into a circularly cylindrical part 14 the diameterof which corresponds at least substantially to the maximum diameter ofthe conical surface 16. Rounded transitions, which are technicallycaused by the cold heading process, can result in the region of theboundary between the conical surface 16 and the circularly cylindricalpart 14 and also at the transition from the circular cylindrical part 14and its free end face 39. Furthermore, the functional element 10 that isshown has a neck part 18 which merges into a rivet section 20. Theboundary between the neck part 18 and the rivet section 20 lies at 22.The body 16 of the functional element 10 has moreover a bore 26 with athreaded cylinder 28 arranged concentrically to the longitudinal axis24. At the lower end of the rivet section 20 in FIG. 1 the rivet sectionpasses into a cylindrical projection 30 which can be regarded asbelonging to the rivet section 20. The bore 28 of the nut element 10has, in the region of the cylindrical projection 30, a region 32 with adiameter which is slightly larger than the base diameter of the threadcylinder 28.

The conical surface 16 extends specifically between the boundary to thecircular cylindrical part 14 of the functional element up to theboundary 36 to the neck part 18 and has a cone angle α of 90° in thisembodiment. It should be emphasized that the circular cylindrical partcan in principle have any desired length in the axial direction 24 andthe circular cylindrical part can also be missing completely so that theend face 39 of the functional element lies at the position of themaximum diameter of the conical surface 16, i.e. at 34 in FIGS. 1 and 3.

The circular cylindrical part 14 can also have a diameter which issignificantly smaller than the maximum diameter of the conical surface16 so that a step is present at the boundary 34 in FIGS. 1 and 3. Thepart 14 could also be formed as a part which tapers away from theboundary 34 in the direction away from the conical surface 16.

The circular cylindrical part could, if desired, have a differentperipheral shape. For example it could have a polygonal or grooved shapein plan view or be made conically divergent or tapering or stepped. Itis important that it does not have any dimension at the boundary surfaceto the conical region which is larger than the largest diameter of theconical region and thus does not form a ring flange there. When it ismade conically divergent the enclosed cone angle must be smaller thanthat of the conical region and irrespective of what shape it has, noextending region may be supported at the sheet metal part and serve as aflange part. At most a few corners may be omitted to dig into the sheetmetal part and serve as a security against rotation, but with a designof this kind being, if anything, undesired. These statements are to betaken into account in the interpretation of the term “circularcylindrical part”, i.e. this term is to be interpreted accordingly.

Features 38 providing security against rotation are uniformlydistributed around the conical surface and here have the form of noseswhich respectively extend in axial planes of the element. Eight suchnoses 38 providing security against rotation are provided here, it couldhowever be more or fewer. The noses providing security against rotationcould also have the form of recesses or noses providing security againstrotation and recesses providing security against rotation could beprovided, for example alternately around the conical surface.

FIG. 2 shows a sheet metal part 40 which has been prepared to receivethe functional element 10 of FIG. 1. Specifically the sheet metal part40 has a conical recess 42 with a hole 44 in the base region of theconical recess. The cone angle of the conical region 42 of the sheetmetal part 40 corresponds preferably to the cone angle α of the conicalsurface 16 of the functional element 10. The hole 44 has a diameterwhich corresponds to the diameter of the neck part 18 of the functionalelement 10 of FIG. 1. The hole 44 could also have a larger diameter, forexample in the range of 0.2 mm larger in order to enable easierintroduction of the functional element into the hole. It would also beconceivable to make the hole 44 fractionally smaller than the diameterof the neck part 18 whereby the hole 44 will be slightly dilated onintroduction of the neck part 18 through the hole 44. The conical shapeof the recess 42 facilitates in any event the alignment of thefunctional element 10 with the sheet metal part on the introduction ofthe functional element. The axis 46 of the hole 44 is thereby alignedwith the longitudinal axis 24 of the functional element 10.

The sheet metal preparation normally takes place in a press or in astation of a progressive tool. In a further press (or in the same press)or in a further station of a progressive tool the functional element 10is then introduced into the sheet metal part 40 using a setting head andattached to it, with the component assembly which results being shown inFIG. 3 and being explained in more detail in the following. It shouldbriefly be emphasized that the attachment of functional elements tosheet metal parts in presses and in progressive tools or using robots orspecial frame devices is well known per se and will not be explainedhere in detail.

The component assembly situation in accordance with FIG. 3 allows it tobe seen that a ring bead 50 is formed from the rivet section 20 of thefunctional element by displacement of material of the rivet section inthe direction towards the ring flange 14. This ring bead 50 forms,together with the neck part 18 which is only slightly deformed ondisplacement of the material of the rivet section for the formation ofthe ring bead 50, a clamping recess for the edge region 48 of the hole44 of the sheet metal part 40 and serves for a corresponding press-outresistance in the opposite direction to the arrow direction 47 in FIG.3. The conical region of the sheet metal part 40 adjacent to the conicalsurface 16 takes care of a corresponding pressing resistance. Althoughnot shown here the displacement of the material of the rivet section inthe direction towards the ring flange 14 takes place in a die which hasa conical recess which enters into contact against the outer side of theconical region 42 of the sheet metal part, so that the sheet metalmaterial is simultaneously pressed radially inwardly whereby aform-fitted engagement arises between the sheet metal material in theconical region 42 and the features 38 providing security againstrotation.

On displacement of the material from the region of the rivet sectiontowards the ring flange pressure is exerted from above in the arrowdirection 47 onto the end face 39 of the functional element 10. Sincerelatively much material is present in the body part 12 of thefunctional element between the end face 39 and the rivet section thisregion of the functional element is not deformed so that a deformationof the thread cylinder 28 need not be feared. The cylindricalcontinuation 30 of the rivet section is not deformed during theattachment of the functional element but rather only guided in a bore ofthe (not shown) die. During the attachment of the functional element ofthe sheet metal part a ring-like hold-down member can be used at thesetting head which is arranged around the cylindrical part 14 and whichpresses the sheet metal part adjacent to the conical recess 42 against aplanar ring surface at the end face of the die that is used, with thisring surface extending parallel to the sheet metal part 40 in the regionaround the conical recess 42. It is also possible to operate without ahold-down member or, if present, to receive the circularly cylindricalpart 14 in a recess at the free end of a plunger of a setting head, sothat the end face of the plunger lies flush with the side of the sheetmetal part remote from the rivet bead after the pressing in of thefunctional element and thus functions as a hold-down member or pressesthe sheet metal part flat around the conical recess.

The component assembly in accordance with FIG. 3 has amongst otherthings the advantage that a further component can be attached to the oneor other side. For example a component can be secured to the end face39, in this case by means of a bolt which, coming from above in FIG. 3,is screwed into the thread cylinder 28. Through the conical design ofthe region 42 of the sheet metal part and the design of the ring bead 50the attachment of the functional element to the sheet metal part is sofirm, i.e. stiff, that the attachment of a component to this end face 39is straight forwardly permissible. In this connection the height of thecircular cylindrical part 14, i.e. the axial thickness of this part canbe selected in order to ensure a spacer function between the furthercomponent and the sheet metal part 40. If the conical part is omitted,then the end face 39 can lie flush with the upper side of the sheetmetal part 40 or higher or lower than this.

The possibility also exists of attachment a component to the lower sideof the sheet metal part 40 in FIG. 3. In this case the bolt would beintroduced from below into the thread cylinder 28. The component couldbe supported at the lower side of the sheet metal part opposite to theconical part 16 of the functional element 10 or at the lower side of thering bead 50 or, with suitable dimensioning of the cylindricalprojection 30 at the free end face of this projection. The cylindricalprojection 30 could also serve as a bearing surface for a rotatable partwhich is likewise secured with a bolt which is introduced into thethread cylinder 28 coming from below.

The FIGS. 4 to 10 show a further example of a functional element inaccordance with the invention here in the form of a bolt element.

In the following description the same reference numerals will be usedfor parts which have the same shape or function as in the nut element ofFIGS. 1 to 3, but increased with the base number 100. It can be assumedthat the previous description also applies for the correspondinglynumbered parts of the embodiment of FIGS. 4 to 9, unless something isstated to the contrary.

The bolt element 110 has a head part or body part 112 which correspondsat least substantially to the body part 12 of the nut element of FIG. 1and the bolt element has moreover a shaft part 113 which extends awayfrom the top side 139 of the circular cylindrical part 114. The shaftpart 113 carries a thread cylinder 128 and ends in a guide spigot 129,for example in accordance with EN ISO 4753.

The circular cylindrical part 114 merges in this example via a ring-liketransition 134 into a conical contact surface 116 which directly mergesinto a rivet section 120 which is equipped here at its lower end 121with piercing and riveting features which can in principle be identicalto the piercing and riveting features of the customary SBF bolt, whichhowever preferably has the form in the German patent application101470076.2. I.e., one can imagine the bolt element in accordance withFIGS. 4 to 7 in such a way that now no neck part is provided, which isbasically also possible in the embodiment of the functional element inaccordance with FIGS. 1 to 3. On the other hand, the upper region 118 ofthe pierce and rivet section 120 is here at least substantially notdeformed, as can be seen from FIG. 7, so that this region could,optionally, be termed a neck part.

In similar manner to the embodiment of FIGS. 1 to 3 features 138providing security against rotation are provided here which here havethe form of noses. It would also be possible to replace the noses 138providing security against rotation in accordance with FIGS. 4 to 10with recesses providing security against rotation which could have thesame shape as the noses that are shown but which present themselves asrecesses in the conical surface 116 instead of raised portions.

One notes from FIG. 10 that the upper end face 139 of the head part 112of the bolt element lies significantly proud of the plane of the topside 140′ of the sheet metal part 140.

This is in particular of advantage when, as here, the functional elementis intended as an earthing bolt, with one or more eyes or forks ofcurrent transmitting cables being clamped between the lower end face 160of the nut 162 in FIG. 10 and the end face 139 (not shown).

It is a special feature of the earthing bolt of FIGS. 4 to 10 that it isintroduced into the sheet metal part in self-piercing manner with thenut 162 screwed on, using the method which is described in theabove-mentioned patent specification 34 47 006, with the plunger of thesetting head pressing against the ring surface 164 of the nut element.The nut element is screwed onto the bolt element and tightened beforeits attachment so that on subsequent painting of the component assemblyconsisting of the sheet metal part 140 and the bolt/nut combination 110,162, or during the application of another protective coating, the paintor the protective coating does not contaminate the thread in the regionbetween the nut element and the bolt element and thus cannot lead to anincreased electrical resistance in this region. The spanner to tightenthe nut element 162 engages at the tool engagement flanks 168.

Furthermore, the outer diameter of the end face 160 of the nut element162 is made fractionally larger than the end face 139 of the boltelement. In this way it is ensured that no paint or other protectivecoating can contaminate the end face 139, so that on attachment of acable shoe the latter always lies in close contact with this end face ana high quality electrical contact is present here. If the diameter ofthe end face 160 were to be smaller than the diameter of the end face139, then the danger would exist that a paint deposit at the outerperiphery of the end face 139 could prevent the cable shoe contactingthis surface intimately.

The nut element can be embossed at positions such as 166 so that duringthe transport of the unit consisting of the bolt and nut element 110,162 the nut element 162 is not lost.

A protection of this kind can also be achieved in other ways. Forexample the pitch of the thread of the nut element can be selected to befractionally different than the pitch of the thread of the bolt element.It is however also sufficient to tighten the nut element firmly when thesurfaces 160 and 139 lie in close contact with one another.

After the manufacture of the component assembly consisting of the sheetmetal part 160, the bolt element 110 and the nut element 162 andoptionally after installation of the component assembly into a vehiclebody and subsequent painting the nut element is loosened and optionallyunscrewed in order to firmly clamp a cable shoe or a plurality of cableshoes or a flange of a conductive housing or the like between the endface 160 of the nut element 162 and the end face 139 and to provide therequired conductive transition from the bolt element 110 and from thisto the sheet metal part 140. If desired a shaped projection with aspecial profile can be provided at the part 114 or at its end face 139in order to prevent a rotation relative to the bolt element of a cableshoe having an opening of matching shape. On provision of such aprojection the cable shoe is clamped between the end face 160 of the nutelement and the end face of the projection, the shape of the projectionand that of the opening of the cable shoe prevent mutual rotation ofthese components.

Although, with an earthing bolt, the end face 139 of the head part 112should have a significant spacing from the top side of the sheet metalpart, i.e. to the side of the sheet metal part which is remote from therivet bead 150, this is not essential with other bolt elements. The end139 can namely be significantly set back relative to the top side of thesheet metal part, i.e. lies significantly below the top side of thesheet metal, and indeed optionally by more than the sheet metalthickness, although this would not normally be desired. Normally thedesired state would be such that the end face 139 lies flush with theupper side of the sheet metal part 140 around the conical recess, sincethis state favours the screwing on of a further component. Theexplanations given above likewise apply to the nut element of the FIGS.1 and 3.

Since the bolt element of FIGS. 4 to 10 is introduced in self-piercingmanner into the sheet metal part, using the method in accordance withthe German patent 34 47 006, the rivet section 120 is beaded over afterthe piercing of the sheet metal part 140 by means of a correspondingshaping surface of the die that is used, so that it adopts the roundedshape 150 which is shown in FIG. 10. In this arrangement the sheet metalpart is also deformed in the manner which can likewise be seen from FIG.10. On piercing of the sheet metal part a piercing slug 160 ariseswhich, as described in the above-named German patent, is firmly clampedwithin the cylindrical recess 132 in the rivet section 120, whereby, onthe one hand, the problem of removing the piercing slug 160 is avoidedand, on the other hand, an increase stiffness is achieved in the regionof the head part 112. The conical recess 142 in the sheet metal part 140arises during the punching out of the punching slug in thecorrespondingly shaped die, as can be read in the patent specification34 47 006.

The sheet metal material 148 from the edge region of the pierced openingis here clampingly received in the beaded over rivet section 120. Whenthe end face 139 of the head part 112 of the bolt element 110 is flushwith the top side of the sheet metal part or is fractionally set backrelative to the latter, then, on screwing on a further component whichlies flat at the end face 139 and at the surrounding sheet metal acompressive stress is generated in the conical region 142 between thetop side of the sheet metal part and the clamping recess for the edgeregion 148 of the pierced hole formed by the rivet section 120,optionally together with the “neck part” 118.

Although the design of the rivet section 120 of the bolt elements inaccordance with FIGS. 4 to 10 has to be executed in correspondence withthe rivet section of a SBF bolt or of an improved SF bolt (DE10147076.2) this is not essential. One could for example design thisregion in accordance with the design of the rivet section 20 of thefunctional element of FIGS. 1 to 3 and attach the bolt element inaccordance with FIGS. 4 to 10 to the sheet metal part 40 with the sameprocess that was described in conjunction with FIGS. 1 to 3. Thepossibility likewise exists of providing the functional element inaccordance with FIGS. 1 to 3 with a cylindrical rivet section inaccordance with the rivet section 120 of the bolt element of FIGS. 4 to10 and of attaching the nut element in the sheet metal part either inself-piercing manner or using a preceding hole punch in manner known perse.

The rounded end 138′ of the noses 138 providing security againstrotation ensure that the sheet metal part is not impermissibly crackedduring the stamping in process, so that fatigue cracks in the sheetmetal part at the positions of the noses providing security againstrotation, i.e. at the positions of the radial projections 150′ are notto be feared.

Although the bolt element 110 of FIGS. 4 to 10 is introduced inself-piercing manner the element can equally be inserted into apre-holed component if this is desired.

An advantage of the functional element of the invention lies in the factthat with one element a broad range of sheet metal part thicknesses canbe covered, so that for example the functional element of FIGS. 1 to 10can be used with sheet metal parts with thicknesses in the range from0.6 mm to 3 mm or indeed up to 4 mm. These thickness statements shouldnot be understood restrictively and are also not restricted to theembodiments of FIGS. 1 to 10.

The functional elements described here can for example be made from allmaterials which achieve the strength class 5.6 or higher. Such metalmaterials are normally carbon steels with 0.15 to 0.55% carbon content.

In all embodiments all materials can be named as examples for thematerial of the functional elements which, in the context of colddeformation, achieve the strength values of class 8 in accordance withthe Iso standard, for example a 35B2 alloy in accordance with DIN 1654.The so formed fastener elements are suitable amongst other things forall commercially available steel materials for sheet metal parts whichare capable of being drawn and also for aluminium or its alloys.Aluminium alloys, in particular those with higher strength can be usedfor the functional elements, for example AlMg5. Functional elements ofhigher strength magnesium alloys such as for example AM50 also come intoquestion.

1. A functional element (10; 110) for attachment to a sheet metal part,such as for example a nut element (10) or a bolt element (110) having abody part (12; 112) or head part respectively which has at a first axialend, if required, a circularly cylindrical part (14; 114) and whichmerges at a second axial end into a cylindrical rivet section (20; 120),wherein the body part (12; 112) is provided in the region between thefirst axial end, or any circularly cylindrically part provided there,and the rivet section (20; 120) with an at least substantially conicalregion (16; 116) which forms a contact surface for a correspondingconical region (42; 142) of a sheet metal part (40; 140), and whereinthe circularly cylindrical part, if present, has a diameter at theboundary (34; 134) to the conical region which is not larger than themaximum diameter of the conical region and thus does not form a ringflange there.
 2. A functional element in accordance with claim 1,wherein features (38; 138) providing security against rotation areprovided in the region of the conical surface (16; 116).
 3. A functionalelement in accordance with claim 1, wherein the axial length of theconical surface (16; 116) of the conical region corresponds at leastapproximately to twice the sheet metal thickness and preferably toapproximately four times the sheet metal thickness.
 4. A functionalelement in accordance with claim 1, wherein the enclosed cone angle (α)of the conical surface of the conical region lies in the range between60° and 150°.
 5. A functional element in accordance with claim 4,wherein the enclosed cone angle (α) of the conical surface of theconical region lies in the range between 70° and 140°.
 6. A functionalelement in accordance with claim 3, wherein the enclosed cone angle (α)of the conical surface of the conical region lies in the range between75° and 115°.
 7. A functional element in accordance with claim 3,wherein the enclosed cone angle (α) of the conical surface of theconical region amounts to about 90°.
 8. A functional element inaccordance with claim 1, wherein the conical surface (16; 116) of theconical region merges via a cylindrical neck part (18; 118) into therivet section (20; 120).
 9. A functional element in accordance withclaim 8, wherein the neck part (18; 118) has an axial length whichcorresponds at least approximately to the sheet metal thickness.
 10. Afunctional element in accordance with claim 2, wherein the features (38;138) providing security against rotation have the form of noses whichare provided at the conical surface (16; 116).
 11. A functional elementin accordance with claim 10, wherein the noses (38; 138) providingsecurity against rotation extend in axial planes.
 12. A functionalelement in accordance with claim 9 or claim 10, wherein the noses (38;138) providing security against rotation extend at the conical surfaceover at least substantially the axial length of the conical region. 13.A functional element in accordance with claim 10, wherein the featuresproviding security against rotation have the form of recesses providedin the conical surface.
 14. A functional element in accordance withclaim 13, wherein the recesses forming the features providing securityagainst rotation are arranged in axial planes of the functional element.15. A functional element in accordance with claim 1, wherein the endface of the body part at one of its first axial end, i.e. at the end ofthe body part remote from the rivet section, and at the end face of anycircularly cylindrical part (14; 114) provided there, forms a supportsurface for a component which is secured by means of the functionalelement (10; 110) to the sheet metal part (40; 140).
 16. A functionalelement in accordance with claim 15, wherein the axial thickness of thecircularly cylindrical part (14) is selected in order to realize aspacer function between the sheet metal part (40) and a componentattached to the sheet metal part by means of the functional element(10).
 17. A functional element in accordance with claim 1, wherein it isa nut element (10) in which the body part (12) is provided with acentral bore (26).
 18. A functional element in accordance with claim 1,wherein it is a bolt element (110) with a shaft part (113) which isarranged at the side of the body part (112) of the circularlycylindrical part (114) remote from the rivet section (120).
 19. Afunctional element in accordance with claim 1, wherein a plurality ofnoses providing security against rotation are provided at the conicalregion of the functional element, extend over the full length of theconical region in axial planes and are uniformly distributed around thelongitudinal axis of the functional element.
 20. A component assemblycomprising a functional element (10; 110) for attachment to a sheetmetal part, such as for example a nut element (10) or a bolt element(110), and a sheet metal component the functional element having a bodypart (12; 112) or head part respectively which has at a first axial end,if required, a circularly cylindrical part (14; 114) and which merges ata second other axial end into a cylindrical rivet section (20; 120),wherein the body part (12; 112) is provided in the region between thefirst axial end, or any circularly cylindrically part provided there,and the rivet section (20; 120) with an at least substantially conicalregion (16; 116) which forms a contact surface for a correspondingconical region (42; 142) of a sheet metal part (40; 140), wherein thecircularly cylindrical part, if present, has a diameter at the boundary(34; 134) to the conical region which is not larger than the maximumdiameter of the conical region and thus does not form a ring flangethere, wherein a conical region (42; 142) of the sheet metal part istrapped in a ring bead (50; 150) formed from the rivet section andwherein the conical region (42; 142) of the sheet metal part contactsthe conical region of the functional element at least substantially overits full area.
 21. A component assembly in accordance with claim 20,wherein features (38; 138) providing security against rotation areprovided in the region of the conical surface of the functional elementand the sheet material of the sheet metal part (40; 140) in the conicalregion (42; 142) engages in form-fitted manner with the featuresproviding security against rotation.
 22. A component assembly inaccordance with claim 20, wherein the said conical surface (16; 116) hasan axial length corresponding at least approximately to twice the sheetmetal thickness.
 23. A component assembly in accordance with claim 22,wherein the said conical surface (16; 116) has an axial lengthcorresponding to at least four times the sheet metal thickness.
 24. Acomponent assembly in accordance with claim 20, wherein the includedcone angle (α) of the conical surface (16; 116) lies in the rangebetween 60° and 150°.
 25. A component assembly in accordance with claim24, wherein the included cone angle (α) of the conical surface (16; 116)lies in the range between 70° and 140°.
 26. A component assembly inaccordance with claim 24, wherein the included cone angle (α) of theconical surface (16; 116) lies in the range between 75° and 115°.
 27. Acomponent assembly in accordance with claim 24, wherein the includedcone angle (α) of the conical surface (16; 116) amounts to approximately90°.
 28. A component assembly in accordance with claim 20, wherein theconical surface (16; 116) merges via an at least substantiallycylindrically neck part (18; 118) into the rivet section (20; 120). 29.A component assembly in accordance with claim 21, wherein the neck part(20; 120) has an axial length which corresponds at least approximatelyto the sheet metal thickness.
 30. A component assembly in accordancewith claim 20, wherein it is a nut element (10) in which the body part(12) is provided with a central bore (26).
 31. A component assembly inaccordance with claim 20, wherein the ring bead (50) is formed bydisplacement of material of the rivet section (20).
 32. A componentassembly in accordance with claim 20, wherein the rivet section (120) isbeaded over around the edge (148) of the opening (144) of the conicalregion (142) of the sheet metal part (140) to form the ring bead or arivet bead.
 33. A component assembly in accordance with claim 20,wherein the functional element is a bolt element which has a shaft part(113) having a thread which projects away from the end of the conicalregion of the body part (112) remote from the rivet bead or from anycircularly cylindrical part (112) present there or from a projectionprovided at an end of the conical region of the body part (114) remotefrom the rivet bead or at the free end of a circular cylindrical partprovided there.
 34. A component assembly in accordance with claim 33,wherein a nut element is screwed onto the thread of the shaft part andhas a radially extending flange which has, at its end face remote fromthe rivet bead, an engagement surface for a screwing tool and, aroundthis, a ring-like surface for a plunger of a setting head and, at itsend face (160) confronting the end face (139) of the bolt element, or atthe free end of a circularly cylindrical part (114) provided there,contacts the end face (139) and is preferably dimensioned in diameter tobe larger than this end face (139), i.e. overlaps it.
 35. A componentassembly in accordance with claim 33, wherein the projection has aperipheral shape which serves as a projection providing security againstrotation for a cable shoe.
 36. A component assembly in accordance withclaim 34, wherein a cable shoe is located between the nut element (162)and the bolt element.
 37. A component assembly in accordance with claims34, wherein it is provided with a protective coating, not however inregions of the nut element and the bolt element which contact oneanother.
 38. Method for the attachment of a functional element (10; 110)part, such as for example a nut element (10) or a bolt element (110) toa sheet metal part, the functional element having a body part (12; 112)or head part respectively which has at a first axial end, if required, acircularly cylindrical part (14; 114) and which merges at a second axialend into a cylindrical rivet section (20; 120), wherein the body part(12; 112) is provided in the region between the first axial end, or anycircularly cylindrically part provided there, and the rivet section (20;120) with an at least substantially conical region (16; 116) which formsa contact surface for a corresponding conical region (42; 142) of asheet metal part (40; 140), and wherein the circularly cylindrical part,if present, has a diameter at the boundary (34; 134) to the conicalregion which is not larger than the maximum diameter of the conicalregion and thus does not form a ring flange there in accordance, themethod comprising the steps of: manufacturing a conical recess (42; 142)in a sheet metal part (40; 140) to have a cone angle (α) whichcorresponds at least substantially to the cone angle (α) of the conicalsurface (16; 116) of the functional element, with a hole (44) beingprovided in and concentric to the conical recess (42; 142) and with thediameter of the hole corresponding at least substantially to thediameter of the rivet section (20; 120) of the functional element orbeing somewhat larger than this; passing the rivet section (20; 120) ofthe functional element (10; 110) through the hole (44) of the conicalrecess (42; 142) of the sheet metal part so that the conical region ofthe conical recess (42; 142) enters approximately into contact with theconical surface (16; 116) of the functional element and forming a rivetbead (50; 150) from material of the rivet section (20; 120) toclampingly receive the smaller end of the conical region of the sheetmetal part.
 39. Method in accordance with claim 38 wherein the formationof the ring bead (50) takes place by displacement of a region of therivet section (20) of the functional element (10) and in that the sheetmetal material of the sheet metal part (40) is supporting during thisdisplacement in a die which brings the sheet metal material in theconical region into engagement with features of the functional elementproviding security against rotation.
 40. Method in accordance with claim38, wherein the ring bead (150) is formed by beading over the rivetsection (120) and wherein the sheet metal material is supported in a dieduring or after the beading over which brings the sheet metal materialin the conical region (140) into engagement with features of thefunctional element providing security against rotation.
 41. Method inaccordance with claim 38, wherein for the formation of the conicalrecess in the sheet metal part the sheet metal parts supported on thedie is pierced by the free end of the cylindrical rivet section (120) ofthe element to form a stamped slug and is formed into a conical recessin a correspondingly shaped cut-out of the die.
 42. Method in accordancewith claim 41, wherein for the formation of the stamped slug (161) andof the rivet bead (150) pressure is exerted on a ring-like pressuresurface at the free end face of a flange part (164) of a nut element(162) screwed onto the bolt element (110).